I assume that you are referring to vibrating platforms sometimes used for pilates. Supposedly they were developed for astronauts to prevent muscle atrophy, maintain bone density/strength and for toning while in a zero-G environment.

I've seen one of the pilates vibrating platforms in a friend's upscale health club. I've not tried it myself or have hear much feedback about it. My friend says she's not tried it either or paid much attention to it. After seeing this thread, I did a bit of research on these platforms. From limited reading on the subject, i get the sense that these platforms may very well provide some benefits but probably nowhere as much as the exaggerated claims made by platform manufacturers.

EVERYTHING claims it improves blood flow. But blood flow is generally already optimal to your tissues, and circulating volume is essentially fixed, so you can't improve blood flow to one tissue without reducing it to another. It is generally nonsense.

I don't like how the vibrations are transmitted through the body, some gets transferred to the brain.
I don't like the rapid back and forth motion on joints, not sure how they will hold up after long term use.